Synthesis of a polypeptide with ACTH-like structure

Zusammenfassung Es wird über die Synthese eines Icosapeptides, das aus den zwanzig ersten Aminosäuren des N-Endes eines ACTH Moleküls aufgebaut ist, berichtet. Das synthetische Produkt besitzt eine schwache ACTH-Wirkung.     

Synthesis of a structure proposed for scotophobin

Zusammenfassung Es wurde ein biologisch interessantes Polypeptid mit der für Scotophobin vorgeschlagenen Sequenz synthetisiert. Da dieses nur eine geringe biologische Aktivität besass, wird angenommen, dass die für das natürliche Produkt vorgeschlagene Strukturformel nicht korrekt ist.

---

---

We thank the National Institutes of Health (MH 19320) for the support of this work.     

Synthesis, structure and function of poly-α-amino acids – the simplest of protein models

During the 1950s, linear and multichain poly-α-amino acids were synthesized by polymerization of the corresponding N-carboxyamino acid anhydrides in solution in the presence of suitable catalysts. The resulting homo- and heteropolymers have since been widely employed as simple protein models. Under appropriate conditions, poly-α-amino acids, in the solid state and in solution, were found to acquire conformations of an α-helix and of β-parallel and antiparallel pleated sheets, or to exist as random coils. Their use in experimental and theoretical investigations of helix-coil transitions helped to shed new light on the mechanisms involved in protein denaturation. Conformational fluctuations of peptides in solution were analysed theoretically and studied experimentally by nonradiative energy-transfer techniques. Poly-α-amino acids played an important role in the deciphering of the genetic code. In addition, analysis of the antigenicity of poly-α-amino acids led to the elucidation of the factors determining the antigenicity of proteins and peptides. The synthetic procedures developed made possible the preparation of immobilized enzymes which were shown to be of considerable use as heterogeneous biocatalysts in the chemical and pharmaceutical industry. Interest in the biological and physicochemical characteristics of poly-α-amino acids was recently renewed because of the reported novel findings that some copolymers of amino acids are effective as drugs in multiple sclerosis, and that glutamine repeats and reiteration of other amino acids occur in inherited neurodegenerative diseases.     

Isolation and structure of Phomin

Zusammenfassung Aus Kulturen einesPhoma spec. (Stamm S 298) (Fungi imperfecti) wurde das neue cytostatisch wirksame Antibioticum Phomin isoliert. Auf Grund seiner chemischen und physikalischen Eigenschaften wird ihm die Strukturformel1 erteilt.     

Protein structure and function

Posters

Protein structure and function     

Regulation of glycosaminoglycan structure and atherogenesis

Cardiovascular disease is the major cause of premature death in modern society, and its impact is increasing due to rising rates of obesity and type 2diabetes. Clinical studies based on targeting metabolic abnormalities and biomarkers demonstrate significant benefits, but always an element of disease remains which is resistant to treatment. Recent evidence has strongly implicated an early interaction of atherogenic lipoproteins with vascular matrix proteoglycans as the initiating step in atherogenesis. Expert commentary has pointed to the need for vascular directed therapies to provide reductions in the residual disease component. We propose that the regulation of synthesis and thus structure of glycosaminoglycans on proteoglycans provides a potential pathway to this reduction. We review existing evidence that the vascular synthesis of glycosaminoglycan chains can be regulated in a manner which reduces lipoprotein binding and the potential application of this strategy to attenuation of the current cardiovascular disease pandemic.Received 21 October 2003; received after revision 16 December 2003; accepted 29 December 2003     

The structure of napelline and songorine

Zusammenfassung Für das Aconitum-Alkaloid Napellin wurden auf Grund einer eingehenden Diskussion des Tatsachenmaterials die Strukturen XI bzw. X vorgeschlagen. Das Alkaloid Songorin ist das dazugehörige Ring-D-Keton.     

Synthesis of Seselin and its hydroderivatives

Zusammenfassung Die Synthese des Naturstoffes Tetrahydroseselin aus der FruchtSeseli indicum wird beschrieben.

---

---

Part X of a seriesCoumarins and Related Compounds. Part IX, A. K.Das Gupta, R. M.Chatterje and K. R.Das, J. chem. Soc. (C), (1969), 2618.     

Ontological reduction and molecular structure

In this paper I outline how the debate concerning the intertheoretic reduction of chemistry reaches a stalemate. One way forward is to switch discussion to the issue of ontological reduction and emergence, so I present a counternomic criterion of emergence that should be acceptable to both sides of the discussion. I then examine the bearing on this debate of the symmetry problem in molecular quantum mechanics, as presented by Woolley and Sutcliffe (1977). I conclude by addressing some objections to emergentist positions: that they posit miraculous violations of physical laws; that emergence is obscure and of doubtful coherence; that causal theories of property identity render emergence, under the counternomic criterion, metaphysically impossible.     

Influenza hemagglutinin structure and antigenicity

Cellular and Molecular Life Sciences -     

RNA-splicing endonuclease structure and function

The RNA-splicing endonuclease is an evolutionarily conserved enzyme responsible for the excision of introns from nuclear transfer RNA (tRNA) and all archaeal RNAs. Since its first identification from yeast in the late 1970s, significant progress has been made toward understanding the biochemical mechanisms of this enzyme. Four families of the splicing endonucleases possessing the same active sites and overall architecture but with different subunit compositions have been identified. Two related consensus structures of the precursor RNA splice sites and the critical elements required for intron excision have been established. More recently, a glimpse was obtained of the structural mechanism by which the endonuclease recognizes the consensus RNA structures and cleaves at the splice sites. This review summarizes these findings and discusses their implications in the evolution of intron removal processes. Received 24 August 2007; received after revision 24 November 2007; accepted 27 November 2007     

Synthesis of koenigicine

Summary The structure of koenigicine as 8,9-dimethoxy-3,3,5-trimethyl-3, 11-dihydropyrano-[3,2-a] carbazole (1) has been confirmed by synthesis.     

Synthesis of bombesin

Riassunto Viene riportata la sintesi della piroglutamil-glutaminil-arginil-leucil-glicil-asparaginil-glutaminil-triptofanil-alanil-valil-glicil-istidil-leucil-metioninamide, un peptide identico per proprietà fisiche, chimiche e biologiche alla bombesina.     

A model of nucleolar structure and behaviour

Zusammenfassung Ein mathematisches Modell wird beschrieben, wobei der Nukleolus als offenes System die fibrilläre RNS und die Ribonukleoproteingranula als Komplexstruktur aufgefasst werden. Die Formeln verwenden: Kerndurchmesser, Geschwindigkeit der Bildung von fibrillärer RNS, Moleküllänge, Halbwertszeit ihres Zerfalls sowie die Dichte der Ribonukleoproteingranula.     

Synthesis of phyllocaerulein

Riassunto Viene riportata la sintesi della piroglutamil-glutamil-tirosil(0-solfato)-treonil-glicil-triptofanil-metionil-aspartil-fenilalanilamide, un nonapeptide identico per proprietà chimiche, fisiche e biologiche alla Phyllocaeruleina.     

The structure and functions of the presenilins

The presenilins (PSs) were new proteins discovered in 1995 to be involved, among other functions, in the molecular mechanisms leading to Alzheimers disease. These proteins have been the subject of many investigations since then to elucidate their molecular structures and functions. Until now, the conclusions about PS structure have been discordant, but the 8-TM structure has been accepted by the Alzheimers community, with the evidence for the 7-TM structure largely ignored. Here the evidence is reviewed for the 6-TM, 7-TM, 8-TM and other proposed models of PS topography and possibilities offered for the differences in interpretation of the various sets of data. The conclusion is that at this stage, the 7-TM model for cell surface PS is most likely the correct one.Received 22 December 2004; accepted 26 January 2005